package f.h.dragon.filter;

/**
 * StringFilter:  String filter interface
 *
 * @author Wenlong Meng(wenlong.meng@gmail.com)
 * @version 1.0 at 2012/04/27
 * @since 1.0
 */
public interface StringFilter {
	
	//Logic
	/**
	 * encode the specified str string
	 * 
	 * @param str
	 *            The str string to be filtered
	 * @return null - if str is blannk
	 * @throws NullPointerException - if str is null
	 */
	String encode(String str);
	
	/**
	 * decode the specified str string
	 * 
	 * @param str
	 * @throws NullPointerException if str is null
	 */
	String decode(String str);

}
